My supplies and method :
I always keep a notebook in my camera bag for pressing plants. No matter where you go there is always an opportunity to find something pretty to press. I like these moleskin notebooks. I'm currently using a generic version I bought at Target when I really needed one but couldn't wait on ordering one. You, of course, can use a larger notebook but I like that this size is compact and fits in my back pocket when I'm out exploring. Another thing I looked for when purchasing a pressing notebook is one that has a strap to keep it closed so my plants aren't falling out all over my bag.
After I've emptied out my findings for the day I transfer all the plants to my dining room table where I sandwich them between layers of paper towels and then stack heavy books on top. I leave them like this for a week or so. Every specimen is different and the drying time really depends on how big, how fresh, and what it is. Feel free to check on the progress of your plant at any time during the drying process.
If you have more plants at one time to press than what will fit on the paper towel you're going to need to make layers of books and paper towels. It should be like this - table, paper towel, plants, paper towel, book, paper towel, plants, paper towel, book and so on. It's definitely okay to put more than one specimen or kind of specimen per paper towel sandwich. But try not too put big juicy plants with small nearly dry ones or the moisture from the big one may compromise the quality of the small one.
here's a similar one to what I use) and tape down my plants with some washi tape. I tape them down because it holds them in place, looks nice and keeps them organized but also so I can remove them if I ever want to use them for another project. The ones that don't get organized in the notebook are sandwiched between new dry paper towel layers and stored between pages of books.
• Press your plants immediately. I always find it best to press things as soon as I find them or pick them.
• Press the prettiest! Let me state the obvious here, your plant isn't going to get any prettier after being pressed! Make sure you choose the one from the bunch that is healthiest looking, and doesn't have any physical defects.
• Press fresh things. You really don't want to press plants that are already dry or dead, they'll just crumble.
• Remember that however you put them in your notebook is how they're going to look when they're done. Arrange all stems, leaves and other parts exactly how you want them to be when they're dry before you close up your notebook or sandwich them between paper towels.
• Make sure your specimen is dry to the touch. Carefully wipe off any moisture before pressing.
• Use paper towels that are flat and do not have a bumpy design on them or else that design will be imprinted on your plants like the flower below.
• Leaves of any sort. Just make sure they're not wrinkly to begin with.
• Ferns. Ferns are probably the easiest thing to press and they almost always turn out pretty.